Process of and apparatus for cracking hydrocarbons



Dec. 29, 1925- F. B. KOONTZ PROCESS OF AND APPARATUS FOR CRACKING HYDROCARBONS Filed May 8, 1924 5 Sheets-Sheet l .[Twe rater, .1617. f ioontz L m 2. K. FL 'L? Dec. 29, 1925- 1,567,062

F. B. KOONTZ PROCESS OF AND APPARATUS FOR CRACKING HYDROCARBONS Filed May 8, 1924 3 Sheets-Sheet 2 sq zq 37 3 Sheets-Sheet -I:

Dec. 29, 1925- F. B. KOONTZ PROCESS OF AND APPARATUS FOR CRACKING HYDROCARBONS Filed May 8, 1924 v, M... Dec. 29, 1925.

UNITED-STATES PATENT OFFICE.

i FREDERICK B. KOONTZ, OF TULSA, OKLAHOMA, ASSIGNOR TO COSDEN & COMPANY, OF

- TULSA, OKLAHOMA, A CORPORATION OF OKLAHOMA.

PROCESS D APPARATUS FOR CRACKING HYDROCARBONSa y I Application filed May 8,

'One of the objects is to produce a cracking system wherein the cracking operation can be carried out"continuously for a relavtively longperiod, and this object is accomplished partly by the elimination of carbbn from the passageways in which it would otherwise accumulate and prevent free transmission of fluid therethrough. More specifically stated, the method and apparatus herein disclosed include certain features preventing the formation of excessive carbonaceous obstructions in the course of the vapors, and the danger of such deposits in the highly heated cracking zone and destructive consequences thereof are almost entirely eliminated Y The preferred form of the invention comprises a combination of cooperating elements whereby these and other useful results are efl'ectively accomplished and the advantages of each step preserved while the cracking zone is at a temperature high enough to create an intense cracking reaction followed by free and rapid vaporization. The cracking temperature may be effectively obtained in a highly heated tube or coil discharging nto a separating chamber where the vapors are rapidly releated and discharged to a reflux condenser. However if the vapors were discharged ate very high velocity to the reflux condensen'they would point carbon-forming fractions, and this carbonaceous matter would either accumlate I in the vapor passage and form obstructions-w 1 i of op rationwou d e thus shortened y'obr' carry particles of carbon'and high boiling j 1924. Serial No. 711,866.

structions in the vapor passage, or by carbonaceous matter passing with the reflux condensate to the highly heated cracking zone where it would tend to obstruct the flow and incur the liability of dangerous overheating, where it lodges against the intensely heated surfaces.

With these conditionsin view, the preferred form .of the invention includes the sepa ration and removal of carbonaceous matter from the vapors passing from the separating chamber to the reflux condenser. This carbonaceous material is preferably returned to the separating chamber from which it can be readily removed with the residue and discharged from the system, while the clean vapors pass into the reflux condenser to form clean reflux condensate, the latter being returned to the hot cracking zone. Therefore,

the cracking operation can be carried on for an indefinite period without incurring the usual danger and expense resulting from carbonaceous obstructions in the vapor line or in the cracking zone.

Another object is to increase the yield of low boiling point fractions, which is most effectively accomplished by a combination'of conditions to be hereafter described, though an increase in the yield is promoted by the high temperature and the provision for free evaporation of the residual liquid in the separating chamber. This residual liquid contains carbonaceous matter which is preferably discharged from the system, but it also includes fractions which will evaporate at a high temperature and pass to the reflux condenser for continued refluxing to the cracking zone. High temperature in the separating chamber would therefore increase the yield by evaporation of relatively low boiling point fractions from the residue, and if the temperature is high enough the yield will be further increased by a continued cracking reaction in the separating chamber.

I prefer to maintain a cracking temperature in the separating chambenibut it is also dejsirable to preheat the charging stock by feeding itinto the reflux condenser, and if this fresh stock is subjected to a substantial cracking reaction in the reflux condenser, 'carbgn will be formed therein and transmitted to the intake end of the cracking zone where carbon is a source of danger and most undesira e! To maintain a cracking condition in the separating chamber and at the same time prevent material cracking of the charging stock in the reflux condenser, I; prefer to reduce the temperature of the vapors passing from said chamber to the reflux condenser. This operation also aids in the separation of carbon from the vapors passing to the reflux condenser, as will be hereafter explained. The yield can be thus increased by the cracking and free' evaporation of fractions which .would otherwise be discharged in the residue, and this condition requiring a high cracking temperature in the separating chamber is produced without any material cracking and resultant carbon deposits in the reflux conobtain this result, a very large percentage of the vapors should be condensed in the reflux condenser, preferably more than 70 per cent and usually between 80 and 90 per cent.. The

invention includes a combination of operations particularly adaptedfor the recracking of the reflux condensate and the control of various operating conditions, as will hereafter explained.

An important object of the invention is to maintain a predetermined and substantially uniform cracking condition in the cracking zone. It is of course desirable to obtain an intense cracking reaction without causing destructive overheating which would convert many of the gasoline fractions into permanent gas, and my object is to con: stantly produce the desired reaction, irrespective of variations in other parts of the system. The hydrocarbons passing through the cracking zone preferably include reflux condensate mixed with preheated charging stock, and the reflux condensate may amount to more than 80 per cent of the mixture,-this being especially true if the system is effectively cont-rolled to prevent escape of high boiling point fractions to the final com denser, and such control is most advanta geous, for it results in a product relatively free from undesirable fractions and causes I such fractlons to remain in the system until they are either converted into the desired product or discharged as residuum. However, the reflux condensation hould be care regulated and cannot otherwise prowith substantial uniformity. other termination of. the entire operation lies in.

the cracking zone where the hydrocarbons are exposed to a very high temperature. Consequently a substantially uniform condition 'in this zone is an important factor not only to provide a constant reaction but also to prolong the operation. In the preferred form of the invention, these results are accomplished by pumping the mixture of hydrocarbons at a high velocity through the \cracking zone, and by regulating the pump to maintain a substantially uniform rate of flow from the DllIIlD to the cracking zone. By establishing and maintaining a substantially uniform high velocity at the pump, the hydrocarbons are rapidly subjected to a uniform reaction, and the unconverted fractions are quickly returned for further cracking.

I will now refer to certain conditions existing in the pump with the understanding that I- am the first to actually produce these conditions, and owing to the results derived therefrom, they are regarded as highly important novel features. The reflux condensate is formed at.a very high temperature.

and a saving of time and fuel is gained by returning it to the cracking zone in. this hot condition. In the preferred form of the invention, the hot" reflux condensateis mixed with preheated charging stock and the mix ture is maintained at a high temperature preferably above 600 F., for example, about 7 50 F. It is desirable to retain in the system a reserve supply of the hot mix ture under a pressure of more than 100 pounds per square inch, the most convenient pressure being that of the reflux condenser which may be several hundred pounds per square inch.

While under these conditions of high pressure and hightemperature, the mixture rapidly transmitted to the pump where the pressure is increased to force the hot fluid through the cracking zone to the separating chamber. The increase in pressure at the pump may amount to'lOO pounds per square inch, but the degree of additional pressure will depend upon conditions in the cracking zone. Under theparticular conditionshereafter given, the hot mixture enters the pump under about 200pounds pressure, and is discharged under a pressure of about 300' pounds per square inch. Furthermore, the mixture while subjected to these high pressures and temperatures, a is very rapidly pumped from. the reserve supply to the cracking zone, the rate. of flow through the pump being preferably in excess of 90. gallons per minute. In an apparatus of the proportions her f r scribed, the not mixture canbe pumped from the reserve supply to the cracking zone at the rate of 115 gallons per minute, but it is to be under-.

In addition to the advantages of retainmg the high temperature and causing a rapld flow and frequent recracking of unconverted fractions, the pump is regulated to maintain a substantially uniform flow which results in a substantially constant and uniform cracking reaction in the cracking zone. The latter feature is quite important. because it pro ides for a most intense cracking reaction to be maintained indefinitelv. Withotit danger of overheating the cracking element. I

In using a pump under the conditions heretofore pointed out. it is very important to maintain a substantially uniform rate of flow through the pump, for the temperature in the cracking zone cannot be varied in accordance with iregular variations in the rate of flow. and if the flow is too rapid the desired cracking reaction will not occur. On the otherhand. if the rate of flow is too slow. the cracking element under high pre'ssure is subjected to the danger of overheat- 9 ing which is liable to cause a rupture and the danger of fire and explosion. Even a relatively slight overheating. may require an immediate stopping of the entire operation, or at least result in destructive con- Version of the hydrocarbons into permanent gas.

Therefore, the reserve supply of hot liquid for the pump is a desirable element of the combination. Irregular refluxing, which is bound to occur at some time during a continuous run of many days or weeks, should.

I the cracking zone.

exposed to the high temperature, thereby producing a foam or gas in the liquid passing to the pump. Prior to the present invention, foam produced in this manner has prevented the successful operation of a pump for the purposes herein set forth. In some cases the gas or foam entering the pump has stopped the pumping operation, the foam or gas bubbles having been compressed without leaving the pump cylinder. In other instances, the foam has resulted in a pumping action so irregular that it was necessary to discontinue the operation on account of overheating in the cracking zone.

To overcome this ditliculty. the invention includes a preliminary treatment of the fresh charge which actual experience has shown eliminates the danger and disadvantages heretofore incurred by gas or foam due to the presence of boiling liquid in the pump, thereby providing for a substantially uniform rate of flow. Briefly stated. the fresh charge is preheated to vaporize and remove its low boiling point fractions, and the resultant hot liquid substantially free 0f aS bubbles. or the like, is transmitted with the hot reflux condensate to the pump. In the preferred formof the invention, the desired result is accomplished by preheating the fresh charge in a heat-exchanger forming part of the reflux condenser. and the preheated liquid is then introduced into the vapor space in the reflux condenser.

Unless some precautions are exercised this preheating may cause a rush of unconverted fractions to the final condenser, or it may fail to prevent the consequences resulting from bubbles or foam in the pump, or in As an illustration of a successful means for accomplishing the desired results, I will hereafter describe a reflux condenser including a heat-exchanger through which the fresh charging stock passes. and a meanswhereby the preheated stock is divided into a plurality of streams and discharged at different elevations into he vapor space. etarding elements can be arranged in the vapor space to retard the charging stock falling from one of said elevations to another. If all of the preheated charging stock were admitted into the vapors near the top of the reflux condenser. some of the. liquid may be carried away by the vapors passing to the final condenser. On the other hand. if all of the charging stock were admitted near the bottom of the reflux condenser. the charge may not be eli'ect-ively preheated and the mixture of charging stock and reflux condensate may include the undesirable foam.

I have discovered that by dividing the preheated charging stock into a plurality of streams which enter the vapor space at different elevations. with retarding elements between them, the low boiling point vapors ti J are pern'iittcd to freely escape from the mitted through the pump without incurringthe above mentioned consequences which have heretofore resulted from foam in the pump.

Another object is to regulate the temperature in a part of the reflux condenser by varying the flow of charging stock therethrough, at the same time maintaining a substantially uniform delivery of charging stock to the cracking zone.

A further object is to control the various factors including temperature in the cracking. zone and reflux condenser, the admission of charging stock, the production of reflux condensate and the rate of flow to the cracking zone, in such a manner that a substantially uniform condition is maintained in each part of the system,.thereby providing for a continuing operation for very long periods with satisfactory operating conditions throughout the entire system.

Vith the foregoing and other objects in view, the invention comprises the process and apparatus and the novel details hereafter described to illustrate the invention, although it is to be understood that the invention comprehends variations and modifications within the scope of the claims hereunto appended.

Fig; 1- is a diagrammatical view of an apparatus embodying the features of this invention.

Fig. 2 is a vertical section on a larger scale showing the upper portions of the reflux condenser.

Fig. 3 is an enlarged vertical section taken approximately on the line 33 in Fig. 1.

Fig. 4 is an enlarged detail view showing one of the connecting members for the tubes forming the cracking coil.

Fi 5 is a diagrammatical view similar to Fig. 1 illustrating another form of the invention.

Before pointing out the details, I will briefly describe the system shown by Figures 1 to 4 inclusive. A designates a furnace containing a cracking coil B where the cracking reaction occurs, the resultant hot mixture being discharged through an insulated pipe 1 to a separating'chamber C. The carbonaceous residue is discharged through one or more of the pipes 2 extending from said chamber to conduct the residue out of the cracking system, as will be here after described. The vapors leaving the separating chamber pass into a reflux condenser D where'the high boiling pointv fractions are condensed while the desired low boiling point fractions pass through a pipe 3 to the final condenser 4.

denser. A pipe 7 extending from reservoir 6 is provided with branches 8 leading to pumps E and E respectively, eachpump having a discharge pipe 9 leading to the intake pipe 10 of the cracking coil B.

The furnace shown by Figs. 1 and 3 comprises a battle wall 11 located between a burner 12 and the coil B, said Wall having 1 ports 13 through which the hot gases pass to the upper portion of the coil. A grid 14' below the coil is provided .with ports 15 of varying dimensions for the escape of products of combustion to a flue 16, the smallest ports being near the flue and the largest being remote therefrom, so as to prevent free escape through the ports nearest the flue and cause a substantially uniform distribution of the heat around the cracking coil.

The cracking coil may be formed by a number of approximately horizontal tubes 17 as shown by Figs. 1, 3 andand couplings 18, usually termed return bends at the ends of the tubes. Removable plugs 19 (Fig. 4) are preferably located in these couplings atbpoints opposite the ends of the respective tu es.

The separating chamber C shown in Fig.

1 is an elongated horizontal cylinder covered with heat-retaining insulation 20 and having openings at the top and bottom normally closed by plates or heads 21. A safety valve 22 is mounted on the chamber C. To distribute the hot fluid discharged from the pipe 1 and permit relatively free escape of vapors therefrom, a spreader 23 may be arranged in said chamber as shown in F ig. 1. The spreader shown is in the form of a cone located directly opposite the discharge end of pipe 1 with the apex of the cone facing the pipe.

The several pipes 2 for the discharge of residue from 4 the separating chamber are located at different points, so when there is an accumulation of thick carbonaceous mattherethrough, and the intake ends of the.

pipes may be located at different elevations so the several valves can be'operated independently of each other to ascertain the approximate level of the'l ouid inthe sena The residual matter disrating chamber.

charged through pipes 2 passes to a' pipe 24 which may lead to a storage tank, the valve being normally closed to prevent return of this matter to the cracking coil.

As an illustration of a suitable reflux condenser in Figures 1 and 2 I have shown a large vertical tower or Cylinder 26 above the separating chamber, a heat exchanger including a horizontal drum 27 in direct communication with the cylinder 26 and covered with protective material 28, and an aircooled drum 29 communicating with said heat exchanger and protected by a shield 30. The protective material 28 may be made of insulation to avoid exposure of the heat exchanger to the varying temperature of the atmosphere, and the shield 30 may be made of metal to perform a similar function and to protect the drum 29 from sudden variations due to rain, snow and the like;

To regulate the temperature in the vertical cylinder 26, a. jacket 31 surrounding said chamber is provided with one or more doors, or dampers, 32 which may be adjusted to control the admission of air to the bottom of the jacket. the top of said jacket being open at 33 to permit escape of the air. The air cooled drum 29 at the top of the reflux condenser (Fig. 2) has end walls 34 and air-conducting 1 tubes 35 extending through said walls. The tubes are open for the delivery of air therethrough, and the flow of air may be regulated by adjusting the valves, or dampers, 36 shown in Fig. 2. The outgoing vapors, contacting with the outer faces of the tubes 35, are deflected by baflle plates 37 to flow in the course indicated by an arrow in Fig. 2.

The heat exchanger shown most clearly in Fig. 2, comprises the drum 27 having .end walls 38, vertical partitions 39 and a horizontal partition 40. These elements are combined to form an intake compartment 41,. a transfer compartment 42 and a discharge compartment 43. A baflie plate 44 is located in the heat exchanger to deflectthe vapors as indicated in Fig. 2. 45 designates oilconducting tubes extending through the partitions 39. In a manner to be more fully explained, the cool fresh charge is pumped through pipe 46 and into the intake compartment 41 from which it escapes through the lower group of tubes 45 below baflle 44 to the transfer compartment 42 and then through the upper group of tubes 45 to the compartment 43 where it is discharged through a pipe 47 equipped with a valve 48 (Fig. 1) to regulate the discharge of surplus charging stock which may be returned to the source of supply (not shown) or otherwise suitably disposed of. However, the pipe 47 is provided with the branches 5 for the delivery of the preheated charging stock t0 the vapor space, and each branch 5 (Fig.

1) is provided with a valve to regula e the admission of charging stock.

As an illustration of a suitable means for forcing the fresh charge into the cracking system, a pair of pumps F and F is shown in Fig. 1. The charge supplied through pipe 49 may pass through valve 50 to the intake of pump F, or through valve 50' to the in take of pump F.- The fluid discharged from pump F passes through valve 51 in pipe 52 to the pipe 46, and when the pump F is in operation the fluid is discharged through pipe 52 and valve 51 to the pipe 46. A by-pass 53 equipped with a pressureresponsive relief valve 54 connects the discharge pipe 52 with the intake of pump F. A similar by-pass 53 provided with a relief valve 54 connects the discharge pipe 52 with the intake of pump F.

The object in using the two pumps F and F is to avoid stopping the entire' operation when for any reason it becomes necessary to stop the pump. When the pump F is efl'ective, the valves 50 and 51 are open, and the valves 50 and 51' are closed. If it becomes necessary to stop the pump F, the valves 50 and 51 are closed and the companion valves 50 and 51 are opened, the pump F being then used to supply the charging stock. In either case, the active pump may be driven continuously at a substantially uniform speed, and the rate of delivery is regulated by a valve 55 (Fig. 1) in the supply pipe 46. The temperature in the'heat exchanger is thus regulated by adjusting the valve 55 to control the flow of chargmg stock to the heat exchanger. This adjustment will vary the pressure between the valve 55 and the active pump and when this pressure becomes excessive, the pressure-responsive relief valve 54 or 54 is automatically opened to by-pass some or all of the fluid from the outlet to the inlet of the active pump.

The surplus charging stock escaping through pipe 47 is regulated by the valve 48. The admission of charging stock to the vapor space is regulated by the valves in branch pipes 5 through which the preheated charge nters the vapor space of the vertical cylirder 26.

It will now be understood that the delivcry of charging stock through the heat exchanger can be regulated by the valve 55 to maintain a predetermined temperature in this part of the reflux condenser. Regardless of the rate of flow through the heat exchanger, the admission of charging stock to the reflux condensate is regulated by the valves in branch pipes 5. Meters 46 and 47 are located near the valves 55 and 48 to indicate the rate of flow through the pipes 46 and.47.

I have heretofore referred to avoiding the presence of gas or foam in the ump E or E, and the importance of releasing the low boiling point vapors from the incoming charge, as a precaution to prevent the foam ervoir 6. If all of the preheated charging stock were admitted at the top of the vertical cylinder 26, the vapors rushing from the reflux condenser would carry with them some of the charging stock. Or, if all of the charging stock were admitted near the bottom of the reflux condenser, the incoming liquid would reach the reservoir 6 without efl'ectivc removal of the low bo ling point fractions, and the boiling liquid in this reservoir would pass to the pump. Byadmitting relatively small streams of charging stock at diiferent elevations,- with baflles 57 or other retarding elements between them, the charge is thoroughly preheated without incurring any of the above mentioned .disadvantages. The removal of the low ,boiling point fractions from the incoming charge also reduces the production of fixed gas in the cracking zone.

The mixture of preheated charging stock and hot reflux condensate passes from the reserve supply in reservoir 6 and is conducted through pipes 7 and 8 to either one of the pumps E and E. When one of these pumps is active, the other is idle, so a reserve pump is always at hand ready for operation when for any reason it becomes necessary or desirable to stop the active pump. Valves 58 control the delivery of the hot mixture through the pump E, and the valves 59 control the delivery through the pump E. The delivery of steam or other operating medium to the pumps E andE is controlled to mairtain a uniform delivery of the hot hydrocarbon mixture to the cracking coil.

In the preferred form of the invention, the

pumps E and E may be operated by steam, and I have shown valves 60 to regulate the delivery of steam to these pumps. A meter 61 in the pipe 10 indicates the rate of flow from the active pump, and this meter is under the observation of the operator in charge of the pumps E and E.

Near the left side of Fig. 1, 62 designates a pipe equipped with a valve 63 for the admission of steam to the discharge end of the coil. At the end of a run, the valve 64 in discharge pipe 1 may be closed while steam is admitted through pipe 62 and passed backwardly through the coil to clean the same and avoid overheating of carbonforming liquid therein. At this time, a valve 65 near the intake of the coil may be closed while the steam is discharged through a pipe 66 providedwith a valve 67 which is closed during normal operating conditions. The pipe 66 and valve 67 also serve as a means for exhausting the contents of the cracking coil in the event of a fire resulting from leakage in the coil. 7

The pressure of the vapors can be regulated in any suitable manner, and preferably by a valve located at any conv'eniem point. For example, a pressure regulatin valve 68 (Fig. 1) may be located in the a por pipe 3 leading from the reflux conden er to the final condenser. A gage 69 is located adjacent to this valve to indicate the vapor pressure, and the valve is preferably regulated to maintain a substantially uniform vapor pressure at the high pressure side of the valve. A thermometer 70 is located in the vapor line adjacent to the valve 68 to indicate the temperature of the vapors passing to the final condenser at. The temperature of the reflux condenser is preferably regulated to maintain a substantially uniform temperature at the thermometer 70, so that a predetermined and substantially uniform low boiling point product will be obtained from the final condenser.

By grouping together, the thermometer 70, gage 69 control valves 48, 55 and 68, and meters 46 and 47, various elements of the system can be readily controlled by a single operator.

The operation may be carriedout as follows:

At the beginning, when the apparatus is cold and empty and the pressure regulating valve 68 entirely open, the initial charging stock may be admitted through a pipe 71 leading to a pipe 72 connected to the pipes 8. At this time valves 73.and 74 are open and tlievalve 25 is closed. The incoming charge passes through the selected pump E or E and rises in the cracking coil. When the coil is filled, the fire in the furnace is started and regulated by a valve 75 at the burner (Fig. 3). The admission of the charge is preferably continued until a substantial body of liquid is supplied to the separating chamber C. Then the admission of fresh charge is discontinued. The valve 7 6 in the residue line is closed and the valve 73 is also closed, the valves 7-1 and 25 being open. for the direct return of liquid from the separating chamber to the pump E or E. The operation of this pump is continued to circulate the oil from the separating chamber through the coil and back to said chamber. This circulation results in a preliminary heating while the pressure regulating valve 68' is entirely open. so the air and any water vapor resulting from the heating are expelled through the final condenser. The pressure regulating valve 68 is then completely closed and the circulation through the coil and separating chamber is continued until the desired pressure 4 and temperature are obtained. The oil in the separating chamber is then in a highly heated condition, and normal llO Y velocity carryin operating conditions are established by closing the valves 25 and 74 to prevent flow of liquid from the separating chamber to the pump E or E. The valve 68 is regulated to maintain a substantially uniform pressure at the gage 69, and the charging stock is continually admitted through the heat exchanger and branch pipes 5. As the carbonaceous residuum accumulates in the separating chamber, it is removed through one or more of the pipes 2 and discharged through pipe Q-i and valve 76.

The burner 12 is regulated to maintain a substantially constant temperature in the furnace and the pump E or E is regulated tomaintain a substantially constant flow of hot liquid from the reserve supply in reservoir 6 to the cracking oil. A substantially uniform cracking reaction is thus obtained in the coil, and the desired intense reaction can proceed for an indefinite period without *overheating the charge or incurring the danger of rupturing the tubes in the cracking coil.

This mixture is therefore in a highly heated condition when it enters the separating chamber, and this insulated chamber may be maintained at a cracking temperature by the heat derived from the cracking coil. The high temperature resultsin a continuationof the reaction in the hydrocarbons contained in the separating chamber, and a free and rapid evaporation of the relatively low boiling point hydrocarbons in the carbonaceous residue, thereby increasing the yield by preventing undue escape of desirable fractions with the residue. Free evaporation is increased by exposing a large surface of the residual liquid and also by conducting the highly heated vapors in an elongated course over this surface. The

.vapors released at the intake end of the horizontal separating chamber are permitted to flow at a low velocity to the opposite end where they are discharged to the reflux condenser, and while moving slowly through this course some of the carbon carried in the vapor will drop to the residual liquid.

Although importantv advantages are gained by maintaining the contents of the separating chamber in a very hot condition,

.this has heretofore resulted in most objectionable carbon deposits in the reflux condenser, and in the prior systems of this kind of which I am aware, the vapors have passed from the separatin chamber at a] high with them particles of carbon and car on-forming fractions, as pointed out near the beginning of this specification.

tAttention is therefore directed to the vertical conduit 77 through which the vapors rise from the separating chamber to enter the reflux condenser, but it is to be under- Stood that this conduit is merely a prevent the disastrous would be likely to occur if the charge in the large'conduit at a velocity low enough to.

permit free precipitation of carbon, and particles of carbon are thus released from the outgoing vapors and dropped into the residue in the separating chamber. Furthermore, the temperature of the slowlyrising vapors is preferably reduced to condense the high boiling point carbon-Iorming fractions, and this preliminary refluxing in conduit 77 causes the return of such fractions to the residue in the separating chamber. Moreover, the condensed high boiling point fractions falling in conduit 77 aid in releasing and knocking down free particles of carbon suspended in the rising vapors.

The cooling of conduit 77 can be conveniently-effected by exposing its lower portion to the atmosphere. as shown in Fig. 1, and by maintaining the reserve supply at 6 in contact with theiouter face of said conduit, the reserve supply of hot liquid being at a lower temperature than the rising vapors in the conduit.

In addition to providing a precipitation conduit for the return of carbonaceous matter, the conduit 77 is preferably utilized to obtain the important advantage of very high temperatures in the separating chamber and at the same time prevent the production of carbon which would result from a corresp onding temperature in the reflux condenser. If the charging stock in the reflux condenser were exposed to a temperature approximately the same as the temperature preferably used in the separating chamber, the incoming charge would be subjected'to a crackingreaction producing carbon in the reflux condenser. from the very hot separating chamber, I preconsequen'ces which reflux condenser were subjected to an intense cracking reaction. substantial degree of cracking in the reflux condenser and thereby materially reduce the danger of adding carbon to the reflux condensate.

It will now be understood that the precipitation conduit 7 7 or its equivalent. performs a number of important functions, each of which very materially increases the efficiency of the system and enables :the operation to continue indefinitely without incurring the usual danger and expense which has heretofore resulted from carbon deposits in the system.

I will now definitely specifv certain operating conditions and "proportions of the apparatus which have been entirely satisfac- I prefer to avoid any By cooling the vapors passing tory in carrying out the invention, although it is to be understood that the invention is not limited to these particular conditions except as specified in the claims. The temperatures at various points may be as follows:

Between about 440 F. and 480 F. in the "vapors leaving the reflux condenser, and

preferably about 450 F.

Above 600 F. in the. reserve supply of reflux condensate and charging stock in the reservoir 8, and preferably about 765 F. at this point. The reduction in temperature of the fluid passing from reservoir 6 to the intake end of the cracking zone is usually about 15 degrees.

Betwecn about 800 and 900 F. in the stream passing from the cracking coil to the separating chamber, and preferably about 875 F. The liquid in the separating chamber can thus be maintained at about 845 F. near the intake end of said chamber and about 820 F. near the opposite end. In this event, the vapors will enter the precipitation tube 77 at about 840 F. and over 90 per cent of the hot stream entering the separating chamber will usually pass into said tube in the form of Vapor.

The temperature of the reflux condenser is preferably regulated to condense more than "(0 percent of the vapors therein. and to obtain a highly desirable low boiling point product, I usually condense andreturn to the cracking zone between 80 and 90 percent of the vapors inside of the reflux condenser.

The admission of charging stock and the reflux condensing action are preferably reg ulated to produce a mixture in proportions of less than 25 percent charging stock and each steam cylinder being 12 inches in diameter and each oil cylinder being 5 inches in diameter. The increase in pressure due to. the pump may amount to more than 100 pounds per square inch, the object being to increase thepressure sufficiently to rapidly force the stream through the cracking zone and obtain a highly effective cracking reaction herein.

The dimensions of other parts of an ap paratus wherein these various conditions can be obtained and maintained may be as follows:

The tubes 17 may be 3 4 inches inside diameter, and the 84 of these tubes, each about 23 feet long may be connected to form a suitable coil. The separating chamber can be about 6 feet in diameter and about 40 feet long. The reflux condenser is prefer- ,ably unusually large in proportion to the other parts, and it is otherwise designed for effective cooling and regulation of the reflux condensation, so as to provide for the proportions of reflux condensate approximately as heretofore pointed out. For example,the vertical cylinder or tower 26 may be about 5 feet in diameter and about 40 feet high, the'other elements of the. reflux conmore than 75 percent reflux condensate. The" densertbeing roportioned approximately as illustrated, with the exception of thicknesses volume of reflux condensate is preferably 5 to 0 times the volume of added charging stock in the reservoir 6.

The rate of flow from the pump to the cracking coil is preferably in excess of 90 gallons per minute. In the particular apparatus herein described the mixture of reflux condensate and charging stock at a temperature of 765 in the reservoir 6, can be Withdrawn through the pump E or E and forced to the cracking coil at the rate of 115 gallons per minute, and the pump can be regulated to maintain a substantially uniform rate of flow while the relatively clean mixture. substantially free of carbon and gas or foam, is at a temperature of about 750 F. Assuming that the valve 68 is regulated to maintain a pressure of 200 pounds per square inch at the gage 69, the-pressure in the separating chamber and reflux condenser will be about 205 pounds and the hot mixture will enter the pump under a pressure of approximately 205 pounds per square inch The pressure is greatly" increased at the pump to maintain the desired velocity and of material and other elementswhich are enlarged to more plainly appear in the small drawings.

The definite disclosure of dimensions, proportions, etc.,, herein set forth is based upon a system adapted to act upon charging stock such as gas oil or a mixture of gas oil and kerosene distillate at the rate of about 500 barrels per day, so it must be understood that the claims are not in any way limited arranged in the furnace. The hot mixture passing from the coil 'B- is discharged other fuel, instead of oil, and B is a coil I through pipe. 1' into a chamber C, and the" object is-to completely vaporize the mixture asit enters the chamber Q, butsince this. "cannot be entirely accomplished, said cham-' withdrawn through a discharge pipe 2' extending from chamber C and provided with a valve 7 6. To promote this discharge, steam may be injected through a pipe 80 and valve 81 connected to the pipe 2. The vapors issuing from the chamber C enter a vertically elongated precipitation conduit 77' where carbonaceous matter is separated from the rising vapors and dropped into the carbonaceous residue in said chamber. This conduit 77' is cooled by exposure to the atmosphere so as to reduce the temperature of the vapors and condensethe fractions having the highest boiling points. sub stantially as heretofore set forth in referring to the conduit 77. The relatively clean vapors, freed from the precipitated carbonaceous matter, are discharged into a reflux condenser D including a tower 26' provided with baflies 57, and a jacket 27 surrounding the upper endof said tower. The low boiling point vapors pass through pipes 3 and 3 to a final condenser 4. the pipe 3 being provided with a valve 68 to regulate the vapor pressure in the system.

A pump 82 is shown in Fig. 5 to force the liquid into and through the coil B where a high velocity should be maintained, said pump having a discharge pipe 10' connected to the coil. The charge is drawn from a reservoir 6' containing apreheated reserve supply and conducted through an. intake pipe 7' to the pump 82. This reservoir 6' is supplied with hot reflux condensate passing from an annular receptacle (i at the bottom of the reflux condenser and transmitted through pipe 83 to said reservoir 6'. The charging stock is supplied through pipe 46 to the jacket 27' where it is preheated by the outgoing vapors while serving as a heat exchanger to condense the high boiling point fractions in the vapors. To regulate the temperature of the heat exchanger formed in this manner. the jacket .27 may be provided with overflow pipes 8 at different elevations, each pipe 84 being equipped with I a valve to control the flow therethrough.

. fresh charge is supplied to the jacket 27-.

p The vapors generated by preheating the charge in jacket 27 escape through a pipe 86 connected to the vapor pipe 3.

Instead of transmitting the reflux condensate from the receptacle 6 to the reservoir 6, this hot liquid can be conducted to the coil B by means of pipe 83 and a branch pipe 87. In this event, a valve 88 in said pipe 87 will be open and the valve 89 in pipe 83 will be closed. v

In Fig. 5, the lowermost baffle 57 diverts the reflux condensate to the .receptacle 6 to prevent return of this relatively clean liquid through the conduit 77. In Fig. 1, a similar function is performed by the lowermost baflie 57.

To force the liquid, etc. from the cracking coil B at the end of a run when the pumping operation is discontinued, a steam supply plpe 90 is connected to pipe 10, said pipe being equipped with a valve 91 to control the admission of steam.

I claim:

1. In the art of cracking hydrocarbons, the process which comprises conducting a stream of hydrocarbons through a cracking zone where a cracking temperature is maintained, discharging the resultant highly heated stream into a separating chamber and depositing the carbonaceousresidue in said chamber, maintaining the contents of said separating chamber at a temperature lower than that of said c acking zone but high enough to cause free evaporation of relatively low boiling point liquid in the carbonaceous residue, removing the carbonaceous residue as it accumulates in said separating chamber and discharging it from the system, discharging the vapors in an upward direction from said separating chamber at a velocity low enough to permit free precipitation of carbonaceous matter, at the same time reducing the temperature of the rising vapors to condense high boiling point carhon-forming fractions, continually returning said carb naceous matter and carbon".

forming fractions from the rising vapors to said separating chamber, thereafter condensing the high boiling point fractions in the remaining vapors and thus separating" the relatively clean high boiling ,point condensate from the carbonaceous fractions, mixing additional charging stock with said clean condensate, and continually transmitting the mixture through said cracking zone and into said separating chamber.

2. In the art of cracking hydrocarbons, the process of which comprises conducting a stream of hydrocarbons at a high velocity through a cracking zone where a cracking temperature is maintained, discharging the lUb resultant highly heated stream into a horitively low oiling point liquid in' the' carbonaceous residue, spreading the hot liquid as it enters said chamber to permit relatively free escape of the vapors, removing carbonaceous residue as it accumulates in said separating chamber and discharging it from the system, conducting the vapors from said highly heated stream in a horizontally elongated course and at a low velocity over the surface of the liquid in said chamber, then discharging the vapors in an upward direction from said separating chamber at a ve- 'locity low enough to permit free precipitation of carbonaceous matter in the rising stream of vapors, continually returning carbonaceous matter from the rising stream to said separating chamber, subjecting the relatively clean vapors to a reflux condensing action to obtain clean reflux condensate, mixing said clean reflux condensate with charging stock, and continually passing the resultant mixture through said cracking zone and into said separating chamber.

In the art of cracking hydrocarbons, the process which comprises conducting a stream of hydrocarbons through a cracking zone where a cracking temperature is maintained, discharging the resultant highly heated stream into a separating chamber and depositing the carbonaceous residue in said chamber, maintaining the contents of said separating chamber at a temperature lower than that of said cracking zone but high enough to cause free evaporation of relatively low boiling point liquid in the 5 carbonaceous residue, removing the carbonaceous residue from said separating chamber. discharging the vapors from said separating chamber through a precipitation conduit at a velocity low enough to permit precipitation of carbonaceous material in the vapors releasing and removing carbonaceous material from the course of the vapors in said conduit, then subjecting the relatively clean vapors to a reflux condensing action to obtain clean reflux condensate freed from said carbonaceous material, mixing additional charging stock with said clean reflux condensate, and continuallv transmitting the mixture through saidcracking zone and into said separating chamber.

4. In the art of cracking hydrocarbons, the process which comprises conducting a stream of hydrocarbons through a cracking zone where a cracking temperature is maintained, discharging the resultant highly heated s ream into a separating chamber and depositing the carbonaceous residue in said chamber, maintaining the contents of said separating chamber at a temperature high enbugh to cause free evaporation of relatively low boiling point liquid in the carbonaceous residue, removing the carbonau-eous residue as it accumulates in said separating chamberand discharging it from the system,

discharging the vapors from said separating chamber in an upward direction and in the form of a vertically elongated rising stream at a velocity low enough to permit free precipitation of carbonaceous material in the rising vapors, at the same, time dropping said carbonaceous material from the elongated rising stream of vapors to said separating chamber, then subjecting the relatively clean vapors to a reflux condensing action to obtain clean reflux condensate freed from said carbonaceous material, mixing said clean reflux condensate with additional charging stock, and continually transmitting the mixture through said cracking zone and into said separating chamber. i

5. In the art of cracking hydrocarbons, the process which comprises conducting a' stream of hydrocarbons througlra cracking zone where a cracking temperature is maintained, discharging the resultanthighly heatcd stream into a sepa 'ating chamber and depositing the carbonaceous residue in said chamber, maintaining the contents of said separating chamber at a temperature high enough to cause free evaporation of relatively low boiling point liquid in the carbonasubjecting the relatively clean vapors to a reflux condensing action to obtain clean re flux condensate freed from said carbonaceous material, at the same time heating fresh charging stock and removing low boiling point vapors therefrom, mixing the liquid portion of said charging stock with said clean reflux condensate, transmitting the mixture to a pump and thencethrough said cracking zone and into said separating chamher, and regulating said pump to maintain a substantially uniform cracking condition in said" c 'acking zone. t

(3. In the art of cracking. hydrocarbons, the process which comprises Conducting a stream ofv hydrocarbons through a cracking zone where a cracking temperatureis maintained, discharging the resultant highly chamber, maintaining the contents of a said f separating chamber at a'tem'perature high enough to cause free evaporation of relatively low boiling point liquid in the carbonacecrs residue removing the carbonaceous residue as it accumulates in said separating chamber and discharging it from the system, discharging the vapors from said separating chamber in an upward direction and at a heated stream into a. -:scparating chamber and.

depositing the carbonaceous residue fin sait velocity low enough to permit free precipitation of carbonaceous material in the rising vapors, at the same time dropping carbonaceous material from the rising stream of vapors to said separating chamber, then subjecting the relatively clean vapors to a reflux condensing action to obtain clean the liquid portion of the charging stock with the hot reflux condensate, pumping the hot mixture through said cracking zone and into said separating chamber, and regulating the pump to maintain a substantially uniform cracking condition in said cracking zone.

7. In the art of cracking hydrocarbons, the process which comprises conducting a 1 stream ofhydrocarbons through a cracking zone where a cracking temperature is maintained, discharging the resultant highly heated stream into a separating chamber and depositingthe carbonaceous residue in said chamber, maintaining the contents of said separating chamber at a temperature high enough to 'cause free evaporation of relatively low boiling. point liquid in the carbonaceous 'residue, removing the carbonaceous residue from said separating chamber, discharging the vapors from said separating chamber in an upward direction and at a velocity low enough to permit precipitation of carbonaceous material in the rising vapors, at the same time removing car'- bonaceous material from the course of the rising vapors, subjecting the relatively clean vapors to a reflux condensing action to obtain clean reflux condensate free of said car bonaceous material, at thesame time feeding chargingstock into the vapors and mixing said charging stock with the reflux condensate, maintaining a reserve supply of the mixture in a-hot condition, continually feeding a stream -of the hotmixture from said reserve supply at a uniform rate of flow and forcing the same through said cracking zone and into said separating'chamber.

8. In the art of cracking hydrocarbons, the process which comprises conducting a stream of hydrocarbons through a cracking zone here a cracking temperature is maintained,

I discharging the resultant highly heated stream into a separating chamber and depositing the carbonaceous residue in said chamber, maintaining the contents of said separating chamber at a temperature high enough to cause free evaporation of relatively low boiling point liquid in the carbonaceous residue, removing the carbonaceous residue as it accumulates in said separating chamber and discharging it from the system, conducting the vapors away from said separating chamber and at the same time removing carbonaceous material from the vapors, subjectingthe relatively clean vapors to a reflux condensing action to obtain relatively clean reflux condensate, feeding charging stock into the vapors and mixing said charging stock with the reflux condensate, maintaining a reserve supply of the mixture at a temperature higher than about 700 F., continually feeding a stream of the hot mixture from said reserve supply at a rate of more than about 100 gallons per minute and pumping the same through said cracking zone and into said separating chamber, regulating the pump to maintain a uniform cracking reaction in the cracking zone, and maintaining the cracking zone, separating chamber and said reserve supply under pressures higher than 100 pounds per square inch.

9. In the art of cracking hydrocarbons, the process which comprises subjecting a stream of hydrocarbons to a cracking reaction in a cracking zone, discharging the stream into an insulated separating chamber without greatly reducing the temperature, said chamber being maintained at a cracking temperature by the heat derived from said stream so as to crack some of the constituents of the stream and cause evaporation from the residual liquid in said chamber, conducting the vapors from said cham- Qber at a low velocity through a precipitation the relatively clean vapors to a reflux condensing action, mixing charging stock with the clean reflux condensate, forcing the mixture through said cracking zoneand into said separating chamber, and removing residuum as it accumulates in said separating chamber.

10. In the art of cracking hydrocarbons, the process which comprises conducting a stream of hydrocarbons through a cracking zone and then into a separating chamber, conducting vapors from said separating chamber to a reflux condenser, continually feeding charging stock through a portion of said reflux condenser to preheat the charging stock and cool the vapors, mixing the charg ing stock with thereflux condensate, transmitting the mixture through said cracking zone and then into said separating chamber, maintaining the contents of said separating chamber at a temperature high enough to crack said. charging stock, and preventing material cracking of the mixture of reflux condensate and" charging stock in said reflux condenser by cooling the vapors passing from said separating chamber to said reflux condenser.

11. In the art of cracking hydrocarbons, the process which comprises conducting a stream of hydrocabons through a cracking zone and then into a separating chamber, conducting vapors from said separating chamber to a reflux condenser, feeding charging stock into said reflux condenser and mixing it with the reflux condensate therein, maintaining the contents of sai'd'separating chamber at a temperature above 800 F., to continue the cracking reaction therein and cause free evaporation of the relatively low boiling point fractions therein, cooling the Japors passing from said separating chamber to said reflux condenser and thereby preventing material cracking of the mixture of re flux condensate and charging stock in said condenser, regulating the reflux condensing action and the admission of charging stock to produce a mixture in proportions of less than 25 per cent charging stock and-more than 75 per cent reflux condensate, maintaining a reserve supply of this mixture at a temperature higher than 600 F., continually drawing the hot mixture from the reserve supply and pumping it through said cracking zone and into said separating chamber, and regulating the pump to transmit the hot mixture through said pump and into the cracking zone at a predetermined uniform rate of flow greater than 90 gallons per -1ninute.

12. In the art of cracking petroleum hydrocarbons, the continuous process which comprises passing a stream of hydrocarbons through a cracking coil wherein the stream is heated to a temperature higher than 800 F. under a pressure greater than 100 pounds per square inch, discharging the highly heated stream into a separating chamber where the carbonaceous residue is deposited, maintaining the contents of said chamber at a temperature above 775 to continue the cracking react-ion therein and at the same time. cause free evaporation of relatively low boiling point liquid in the carbonaceous residue, removing residue as it accumulates in said chamber and discharging'it from the system, discharging the vapors from said separating chamber in an upward direction and in the form of a Vertically elongated stream at a velocity low enough to permit free precipitation of carbonaceous matter in the rising vapors, at the same time cooling the vertically elongated rising stream of vapors to condense its fractions of highest boiling point and knock down particles of carbon fromthe using stream to said separating chamber, discharging the remaining vapors into a reflux condenser, supplying charging stock through a portion of the reflux condenser to preheat the charging. stock and cool the vapors, permitting escape of vapors from the-charging stock, condensing in the reflux condenser more than 75 percent of the vapors from said separating chamber, conducting'the remaining vapors to a final condenser, controlling the admission of charging stock in accordance with the reflux'condensing action to maintain in the system reflux condensate and added charging stock in proportions of less than 20 percent charging stock and more than 80 percent reflux condensate, mixing the charging stock with the reflux condensate while in a highly heated condition, maintaining a reserve supply of the hot mixture, continually drawing a stream of the hot mixture from said reserve supply and pumping it through said coil and into said separating chamber, and regulating the pump to obtain a substantially constant pressure and a substantially constant temperature in the mixture discharging from said coil.

13. In the art of cracking petroleum hydrocarbons, the continuous process which comprises passing a stream of hydrocarbons through a cracking coil wherein the stream is heated to a temperature higher than 800 F. under a pressure greater than 100 pounds per square inch, discharging the highly heated stream into a separating chamber where the carbonaceous residue is deposited, maintaining the contents of said chamber at a temperature above 775 to continue the cracking reaction therein and at the same time cause free evaporation of relatively low boiling point liquid in the carbonaceous residue, removing residue as it accumulates in said chamber and discharging it from the system, discharging the vapors from said separating chamber in an upward direction and in the form of a vertically elongated stream at a velocity low enough to permit free precipitation of carbonaceous matter in the rising vapors, at the same time cooling the vertically elongated rising stream of vapors to condense its fractions of highest boiling point and knock down particles of carbon from the rising stream to said separating chamber, discharging the remaining vapors into a reflux condenser, supplying charging stock through a portion of the reflux condenser to preheat the charging stock and cool the vapors, permitting escape of vapors from the charging stock, condensing in the reflux condenser more than 75 percent of the vapors from said sepa rating chamber, conducting the remaining vapors to a final condenser, controllin the admission of charging stock in aceor'ance with the reflux condensing action to maintain in the system reflux condensate and added charging stock in proportions of less than' QO percent charging stock and more than 80 percent reflux condensate, mixing the charging stock with the reflux condensate and maintaining a reserve supply of the mixture at a temperature higher than 7 00 F continually passing a stream of the hot mixture from the reserve supply and pumping it through said coil and into said separating chamber at a substantially uniform rate in excess of 90 gallons per minute, and regulating the-pump to maintain a substantially constant pressure greater than 100 pounds per square inch and a substantially constant temperature above 800 F. in the mixture discharging from said coil.

14. In the art of cracking hydrocarbons, the process which comprises conducting a stream of hydrocarbons through a cracking zone and then intoa separating chamber where carbonaceouszresidue is deposited, conducting the vapors from said .separating chamber to a reflux condenser, condensing more than percent of the vapors in said reflux condenser and separately condensing the remaining vapors, at the same time discharging separate streams of charging stock at different elevations into said reflux condenser so as to permit free escape of vapors at said different elevations without causing xcessive vaporization at one elevation, mixing the liquidportions of the charging stock: with the flux condensate, regulating the admission of charging stock in accordance with the reflux condensingaction to obtain a mixture of less than 20 percenticharging stock and more than 80 percent reflux condensate, and continually transmitting a stream of the mixture through said cracking zone and into said separating chamber.

15. In the art of cracking hydrocarbons, the process which comprises conducting a stream of hydrocarbons through av cracklng zone and then into a separating chamber Where carbonaceous residue is deposited, conductingvapors from said separating chamber to a reflux condenser, feeding charging stock through a portion of said reflux condenser while out of' contact with the vapors, dividing the preheated charging stock into a plurality of streams, discharging said streams at different elevations into the vapors in said reflux condenser so ,as to distribute the va-- pors escaping from said preheated charglng stock, regulating the reflux condensing action to condense more than 70 per cent of the vapors passing from said separating chamber, separately-rcondensing the remaining vapors, regulating the admission of charging stock in accordance with the reflux condensing action to obtain a mixture of less than 20 per cent charging stock and more than 80 per cent reflux condensate, causing a reserve supply of the mixture toiaccumulate and re main in the system, maintaining said reserve supply at a temperature in excess of 600 F.,

'. transmitting a stream of the hot mixture at a'r'ate in excess of 90 gallons per minute from said reserve supply, through a pump and thence through said cracking zone and into said separating chamber, and regulating the pump to maintain a substantially constant rate of flow and a substantially constant pressure and temperature in the mixture passing from said cracking zone to said separating chamber.

16. In the art of cracking hydrocarbons, the continuous process which comprises subecting a stream of hydrocarbons to a cracking reaction in a cracking zone, discharging the resultant mixture into a separating chamber where carbonaceous residue is deposited, transmitting the vaporsfrom said separating chamber to a reflux condenser, regulating the reflux condensing action to condense more than 70 per cent of the vapors, at the same time admitting charging stockto the reflux condenser and preheating it to a temperature above 600 F., discharging the resultant vapors from the preheated charging stock, controlling the admission of charging stock in accordance with the reflux condensing action to produce a mixture in proportions of less than 25 per cent charging stock and more than per cent reflux condensate, maintaining a reserve supply of said m1xture at a temperature in excess of 600 F., constantly pumping the hot mixture from said reserve supply, at a rate in excess of 90 gallons per minute, through said cracking zone and into said separating chamber, subjecting the hot mixture in the pump to a pressure in excess of 200 pounds per square inch, and regulating the ump to maintain a substantially constant and uniform rate'of flow in excess of said 90-gallons per minute.

17. In the art of cracking hydrocarbons, the process which comprises the initial steps of supplying charging stock to cracking coil and separating chamber, heating the cracking coil and pumping the charge from said chamber to the coil and back into said chamber, discharging vapor fromsaid chamber,

which include preventing escape of liquid from said separating chamber to the pump, conducting a stream of hydrocarbon liquid from a reserve supply and pumping the streamthrough said cracking coil and into said separating chamber, permitting escape of vapor through said reflux condenser to said final condenser, continually adding reflux condensate and charging stock tosaid reserve supply and constantly pumping the mixture from said reserve supply, through said cracking coil and into said separating chamber, regulating said pump to maintam posited, means whereby the hot hydrocarbons are discharged from said cracking tube to said separating chamber, said chamber having an outlet for removal of said residue during the cracking operation, a reflux condenser, a carbon precipitator wherein carbon is released and removed from the course of the vapors, said carbon precipitator comprising a conductor through which vapors pass from said separating chamber to said reflux condenser, and means whereby the reflux condensate, freed from said carbon, is transmitted from said reflux condenser to the intake end of said cracking tube.

19. In a cracking apparatus, a cracking tube wherein hydrocarbons are heated to obtain the cracking reaction, a separating chamber wherein carbonaceous residue is deposited, means whereby the hot hydrocarbons are discharged from said cracking tube to said separating chamber, said chamber having an outlet for removal of said residue during the cracking operation, a reflux condenser, a carbon precipitator wherein carbon is released and removed from the vapors, said carbon precipitator comprising a conductor extending upwardly from said separating chamber to receive the vapors passing from said chamber to said reflux condenser, the area of said conductor being large enough to permit free precipitation of carbon in the vapors rising therein, means whereby charging stock is added 'tothe reflux condensate formed in said reflux condenser, and a pump whereby the mixture of charging stock and .reflux condensate is forced through said cracking tube and into said separating chamber.

20. In a cracking apparatus, a cracking tube wherein hydrocarbons are heated to obtain the cracking reaction, a separating chamber wherein carbonaceous residue is deposited, means whereby the hot hydrocarbons are discharged from said cracking tube to said separating chamber, said chamber having an outlet for removal of said residue during the cracking operation, a reflux condenser, a carbon precipitator wherein carbon is released and removed from the vapors, said carbon precipitator comprising a vertical conductor extending upwardly from said separating chamber to receive the vapors passing to sald reflux condenser, said vertical conductor being more than 10 inches in diameter and more than 6 feet high to permit release and free precipitation of carbon in the vapors rising therein, and means whereby the reflux condensate formed in said condenser is transmitted to the intake end of said cracking tube.

21. In a cracking apparatus, a cracking tube wherein hydrocarbons are heated to obtain the cracking reaction, a separating chamber wherein carbonaceous residue is deposited, means whereby the hot hydrocarbons are discharged from said cracking tube to said separating chamber, said chamber having an outlet for removal of said residue during the cracking operation, a reflux condenser, a carbon precipitator wherein carbon is released and removed from the course of the vapors, said carbon precipitator comprising a relatively cool conductor wherein the vapors are transmitted from said chamber to said reflux condenser and at the same time subjected to a preliminary reflux condensation, said relatively cool conductor being in free communication with said separating chamber to permit return of the precipitated carbonaceous matter, and means whereby the reflux condensate, free from, said carbonaceous matter, is transmitted from said reflux condenser to the intake end of said cracking tube.

22. In an apparatus for cracking hydrocarbons, a cracking coil wherein the hydrocarbons are heated to obtain the cracking reaction, an elongated horizontal separating chamber wherein a cracking temperature is maintained, said separating chamber having an inlet near one end communicating with said cracking coil to receive the hot hydrocarbons from said coil, the opposite end portion of said chamber, being provided with an outlet for the vapors from said hot hydrocarbons so that" the vapors released near said inlet are caused to pass through an elongated'course to said outlet, said separating chamber having an outlet for the removal of residue during the cracking operation, a reflux condenser, means whereby charging stock is fed through a portion of said reflux condenser, a carbon precipitator through which vapors are conducted from said separating chamber to said reflux condenser to release and remove carbonaceous matter carried by the vapors, said carbon precipitator comprising a vertically elongated relatively cool conduit extending upwardly from said separating chamber to permit free return of precipitated carbona- I ceous matter and at the same time cool the vapors to prevent material cracking of the charging stock in said reflux condenser, and means whereby the charging stock and reflux condensate, free from said carbonaceous matter, are pumped from said reflux condenser and into said cracking coil.

23. In a cracking apparatus, a cracking tube wherein hydrocarbons are heated to obtain the cracking reaction, a separating chamber wherein carbonaceous residue is deposited, means whereby the hot hydrocarductor being in direct communication with said chamber to permit return of precipitated carbonaceous matter, the upper end of said conductor being extended into the lower end of said reflux condenser and spaced from the wall thereof to provide a reservoir of relatively cool reflux condensate around said conductor, means whereby charging stock is fed into said reflux condenser to mix with the reflux condensate, and a pump through which the mixture is drawn from said reservoirand forced through said cracking tube.

24. In a cracking apparatus, means whereby hydrocarbons are cracked and vaporized, a reflux condenser wherein the high boiling point fractions are condensed, a final condenser for the remaining fractions, said reflux condenser including a heat exchanger wherein charging stock is preheated While out of contact with the vapors, the, vapor space of said refluxcondenser having inlets at difl'erent elevations, meansw hereby separate streams of the preheated charging stock are simultaneously discharged through said inlets, said vapor space being provided with means for retarding the charging stock falling from one of said elevations to another.

25. In a cracking apparatus, a separating chamber wherein carbonaceous residue is deposited, a cracking coil wherein the hydrocarbons are subjected to-a cracking reaction and discharged into said separating chamber, a reflux condenser arranged to receive vapors from said separating chamber, said reflux condenser including a heat exchanger wherein charging stock is preheated v hile out of contact with the vapors, the vapor space of said reflux condenser having inlets at diiferent elevations for the preheated charging stock and said vapor space being provided with means for retarding the charging stock falling from one of said elevations to another so as vto permit escape of vapors from the charging stock at different elevations, means whereby separate streams of the charging stock are simultaneously discharged through said inlets and mixed .vit-h the reflux condensate at different elevations, and a pump whereby the reflux condensate and the liquid portion of the chargmg stock are forced through said cracking coil.

26. In a cracking apparatus, means whereby hydrocarbons are cracked and vaporized,

a reflux condenser wherein high boiling point fractions are condensed, said reflux condenser including a heat exchanger wherein charging stock is preheated while out of contact with the vapors, regulating means to control the delivery of charging stock through said heat exchanger so as to regulate the \apor temperature therein, a conductor through which preheated charging stock from said heat exchanger is admitted to the vapor space in said reflux condenser, and regulating means to control the flow through said conductor irrespective of rate of flow through said heat exchanger.

27. In acracking apparatus, means whereby hydrocarbons are cracked and vaporized, a reflux condenser wherein high boiling point fractions are condensed, said reflux condenser including a heat exchanger wherein' charging stock is preheated while out of contact with the vapors, regulating meansto control the delivery of charging stock through said heat exchanger so as to regulate the vapor temperature therein, a conductor though which preheated charging stock is admitted to the vapor space in said reflux condenser, and regulating means to control the flow through said conductor irrespective of rate of flow through said heat exchanger, said regulating means being adjustable independently of each other, and the outlet of said heat exchanger being provided with a discharge conduit for the sur =plus charging stock.

28. In a cracking apparatus provided with means for cracking and vaporizing hydrocarbons, a reflux condenser wherein high boiling point fractions are condensed, said reflux condenser including a heat-exchanger wherein charging stock is preheated while out of contact with the vapors, a constantly operating pump whereby the charging stock is forced through said heatexchanger, temperature regulating means comprising a valve arranged in the course of the charging stock passing from said pump to control the flow through said heat-exchanger, a by-pass for the return of charg ing stock from the outlet to the inlet of the pump, a pressure-responsive valve arranged in said by-pass to permit said return in response to. excessive pressure at the outlet of the pump, separate regulating means to control the delivery of charging stock from said heat-exchanger to the cracking means, and a discharge conduit for the excess charging stock delivered to said heatexchanger.

29. In the artof cracking hydrocarbons, the process which comprises conducting a stream of hydrocarbons through a cracking zone where a cracking temperature is maintained, discharging the resultant highly heat-ed stream into a separating chamber and depositing carbonaceous residue in said chamber, conducting the vapors from said separating chamber to a reflux condenser, condensing more than 70 per cent of the vapors in said reflux 'condenser, preheating charging stock to a temperature above 500 F. and removing vapor therefrom, regulating the admission of charging stock in accordance with the reflux condensation to provide a hot reserve supply comprising more than 75 per cent reflux condensate and less than 25 per cent preheated charging stock, transmitting the reflux condensate and charging stock while at a temperature above 500 F. and at a rate in excess of 90 gallons per minute through a pump and thence through said cracking zone and into said separating chamber, and regulating the pump to provide a pressure therein exceeding 1 50 pounds per square inch.

heated stream into a separating chamber and depositing carbonaceous residue in said chamber, conducting the vapors away from said separating chamber and at the same time removing carbonaceous material from the vapors, subjecting the relatively clean vapors to a reflux condensing action to obtain relatively clean reflux condensate freed from said carbonaceous material, mixing charging stock with said clean reflux condensate and maintaining a reserve supply of the mixture at a temperature above 500 F., regulating the reflux condensation to condense more than 70 per cent of the vapors, regulating the admission of said charging stock in accordance with said reflux condensation so as to provide in said reserve supply a-mixture of more than 75 per cent of reflux condensate and less than 25 per cent of added charging stock, constantly pumping a stream of said mixture while at a temperature above 500 F. through said cracking zone and into said separating chamber, and regulating the pump to maintain a substantially constant pressure and a substantially constant temperature in the stream passing from said cracking zone.

In witness whereof, I hereunto subscribe my name to this specification.

FREDERICK B. KOONTZ. 

